Corsa 1.0 12v?

Hi, I have just had my engine replaced and since my car turns over but will not start. We have checked everything, fuel/battery/electricals etc. We are now thinking it could be the Coil iginition pack as there is no spark when turning it over. any advice before I buy coil? I don't think the car has an immobiliser as the main keys has a central locking mechanism and the spare does not. By the way we have tried both keys. Please help!!!!